Henry akhimeli



HASHFIBLD.

'SAFETY VALVE.

No. 97,472. Patented Deo. 7, 1869.

Inventar.

MIi-nesses.

HENRY ASHFIELILOF CHICAGO, ILLINOIS.

,Letters Patent No. 97,472, dated December 7, 1,869.

SAFETYLVALVE.

The Schedule referred to in these Letters Patent and making part of the same.

Figure 2 is a plan view of the top of the interior of,

the valve-cover', and

Figure 3 is a plan view of the bottom of the valveseat plate.

Like letters of like kind designate like parts in each ii ure.

g'lhis invention belongs to the class of safety valves fory the escape of steamfrom boilers, intended to be guarded against anyloading, fastening down, or tampering on the part of the engineer; and

It consists in the novel construction of the valve proper, and of its stem.-`

It also consists iugthe peculiar form of the valve itself, and, in combination with it, ot' a sleeve to cover the spiral spring, which is opelatcd by the valve, so that the escaping steam does not come in contact wit-h it; also, in the peculiar arrangement of the devices for regulating' the pressing force of said spring; also, in the means by which the valve-stem is supported above and below the valve; also, in the peculiarl form ofthe top of the 'alve-stem; also, in the false perforated roof, cast into aud with the top of the cover; also, in the braces cast into and .with the bottom ot' the valve-seat. Y. f

A represents the valve-scat plate, and is a circular disk of suitable diameter and thickness, with twoor more braces B cast with it and upon the centre of its bottom..

The braces B arch downward from said bottom, leaving a 'space of the shape ot' a segment of a circle between them and the bottom of the valves`eat.

These braces are perforated at the centre with an opening, C, for the reception of the valve-stem.

The valve-seat plate A is provided, atits centre, with a proper 'valve-seat, 1), tumlcl-shaped, largest at the top. 1

vThe cover E rests upon and is tirmly secured to the 'plate A.

It is a hollow deine-shaped casting, having a false perforated roof, F, cast into and with it. This false roof has a solid centre, and is connected by radial arms with the inside ofthe cover E, and is arched across it near its top.

This cover has also an opening, G, near its top,- for the admission ot" a lever and ears, H, between which the lever is pivoted.

I is the valve, which is of the general form oi' the frustum of `one right cone placed above another, the

larger uppermost, with the smaller .ends of each downward, which form is used for the purpose of keeping the upper part of said valve as cool as possible, and thus protecting the valve-spring resting upon it from heat. This' valve .tits at ,itsbottom with perfect accuracy to the valve-seat D..

A steel spiral spring, K, rests upon the top of the valve, and is regulated by a nut, L, which presses upon its top. 4 i n i The n'ut L works upon a threaded sleeve, M, which extends downward a little way in the interior of the spring K, the upper part of which embraces a washer, N, which protects tbe threads of the sleeve from injury from he spring. y

Above the nut and screwed upon the sleeve M is the nut O," which is circular, and of the same size as the top ot' the valve I.

A framed?, stands' upon and is secured to thevalveseat plate A. rlhe top of the sleeve M passes through ,and is firmly screwed into the top of this frame. l

The valve-stem Q passes through this frame, downward through the sleeve M, the interior of the spring K, the centre of the valve I, and the opening C in the brace B.

'lhe stcmplays loosely at all points except in the valve, in which it is tightly screwed, and at the top terminates in a hammer-shapedhead, It, ritt-ing closely to the top ofthe sleeve M, when the valve I is closed, and provided with a slot for thereceptionbf theend of the lever S, which is pivoted on the ears H, and works in the opening G in thecover. i

A suit-able opening, T, in the top of the cover, per mits the escape of steam. l

The spring K is covered with a cylindrical jacket, -\f',n1a,de ofsuitable sheet-metal, which is firmly secured to the sidcsof the top of the' valve 1, and extends upward, covering said spring K and the nut L, and just enclosesthe bottom ot' the sides oi' the nut O, fitting closely to the same.

In the operation ot' this device the pressure of steam required to move the spring, and thus open the valve, may be ascertained before securing the frame I in. place, by weight upon the lower end ofthe valve-stein; or by a dynainometer attached to the head of the valve-stem. As theA force required to operate thc,

spring and mise the valve increases as the nut L is screwed down toward'the valve, and the spring is thus shortened, a scale or series of marks may be employed to show the force of pressure required to operate the valve at Various positions oi' the nut L.

When .the apparatus is to be used, itis intended that the valve-scat plate shall be the head of the dome, and be trmly secured to it.

It will be seen that by the peculiar construction of this safety-valve, it will be impossible for the engineer', when it is in use, to get at any part of it for the purpose of loading or fastening it down; that the spring, being covered with the jacket V, which moves with the valve, is protected from contact with the steam, and thus it will be uniform at all -times in exerting the same downward pressure, by which greater accuracy will be attained than is possible where the spring is uncovered; that the valve, being supported above and below, in the manner described, cannot trip or get outof order.

I do not claim broadly the invention of a jacket to cover and protect the valve-spring from escaping steam, neither do I claim the method by which said jacket is connected with said Yvalve in the `invention of H. \V. Hewct, patented August 18, 1868; but

What I do claim as my invention, and desire to secure by Lcttcis lateut, is-

1. 'lhe valve l, constructed as shown and described, and operating as and for the purpose set forth.

2. In combination with the valve I, and rigidly attached to its outer upper part, the jacket V, con

5. lhe combination of the sleeve M, the nut L, the v washer N, and the spiral spring K, when constructed as shown and described, and operating as and for the purpose set forth.

(5. The braces B, cast into and with the valve-seat plate, as shown and described, and for the purpose set fort-l i HENRY ASHFIELD.

Witnesses:

SAML. S. MARR, W. H. CLARIDGE. 

